Shufeldt: Birds from Bermuda. 379 



a corresponding series chosen from Shearwaters and other tubinarine 

 birds, one could tabulate the exact difference to be found among 

 them. They would be unimportant in value, however, as compared 

 with bones of other parts of the skeleton presenting more distinctive 

 characters, for example, such as we find in the skull, the sternum, and 

 some of the long bones of the limbs. These remarks apply equally 

 well to the numerous phalangeal joints of the pes. 



The Pelvic Limh (Plate XXVIII). — For the most part, the bones 

 of this extremity seem to enjoy more or less pneumaticity, especially 

 the shafts of those of the thigh and leg. We are struck with the 

 small size and shortness of the femur as compared with the humerus 

 of the pelvic limb. It averages but little over three centimeters in 

 length, its subcylindrical shaft being but slightly bent between its 

 extremities, the convexity being in front, and best marked at about 

 the juncture of middle and lower thirds. 



The " trochanter major '' is but feebly developed, and the summit 

 of the bone is flat and articular, the small caput fcmoris being pro- 

 foundly pitted for the insertion of the ligamentum teres. Distally, 

 the condyles are also small, and present all the usual characters as 

 we find them in the femora of Petrels generally. In Shearwaters the 

 shaft of the femur generally is far more bent or arched than it is in 

 ^strelata and its immediate congeners. In Oceanodroma the shaft 

 of this bone is very straight. 



No patellce occur in any of these collections, and so small as sesa- 

 moid was probably overlooked in collecting. 



Passing to the bones of the leg, I find that the tibiotarsus varies in 

 length as in the case of the other long bones of the limbs. It aver- 

 ages between 6. and 6.3 centimeters in length (PI. XXVIII, figs. 122, 

 123). It has a very straight shaft, which, for its middle third, is 

 subcylindrical in form, and somewhat compressed antero-posteriorly 

 below. 



Proximally, the bone is characterized by a very conspicuous cne- 

 mial process, to which I have referred on a former page of this work. 

 This process is flat and triangular posteriorly; its ectocnemial part is 

 considerably reduced, while the entocnemial portion is expanded and 

 extends directly to the front. The common superior border to these 

 two processes is somewhat thickened and of a sub-hemicircular out- 

 line. As already shown above, this is the general character of the 



